The War on Terror officially started in 2001, shortly after hijacked commercial airplanes crashed into New York City's Twin Towers, the Pentagon, and a field in Pennsylvania. Before September 11, 2001, many Americans hadn't been paying much attention to US military involvement in foreign Islamic conflicts, either directly or in a supportive role. The 911 attack, in which nearly 3000 US civilians died, was perceived by some as coming out of the blue.
Those advocating the desert equivalent of a scorched earth policy recommended that the US respond to the terrorists by "turning their country into glass." Many of those advocates couldn't name which country we should turn into glass, as long as Muslims lived there, because Muslims "hated our freedom," or were jealous of it because they had to live under sharia law. It was an emotional reflex reaction.
Cooler heads prevailed, and by cooler heads, I mean the neoconservatives who had been patiently waiting for years for an opportunity to effect regime change in the Middle East as part of their larger goal of establishing global hegemony for the US. The Statement of Principles of the Project for the New American Century (PNAC) listed these and other goals. Many members of PNAC were part of George W. Bush's administration, and influenced his decision to declare the War on Terror.
The US didn't "turn their country into glass," because 15 of the 19 hijackers were Saudi Arabians, and the only response the US has had to Saudi Arabia regarding 911 is the Senate's recently passing a bill which would allow families of victims of 911 to sue Saudi Arabia. Saudi Arabia has threatened to sell its US assets if this bill passes, and President Obama is considering vetoing it, to avoid disruption in our relationship with Saudi Arabia. The other four 911 hijackers were from United Arab Emirates, Egypt and Lebanon, but the US didn't retaliate against them either.
So no, the US didn't turn Saudi Arabian countries into glass, but it turned into rubble many cities in countries where the Project for the New American Century had been planning to show its muscle well before 911, particularly Iraq. Instead of being defeated, though, Islamic terrorism grew. Over the fifteen years since 911, the US military has fought the war on terror in Afghanistan, Iraq, Syria, Pakistan, Somalia, Philippines, Yemen, Libya. A generation that has known nothing but life in refugee camps continues to provide recruits for terrorists.
An armed Muslim: is he a freedom fighter or a terrorist? With the CIA's covert operations we've hedged our bets, for example, in Sunni vs. Shiite conflicts, so in effect, we've armed and trained militants in one battle that we end up fighting in another. There's other craziness and confusion, too. I haven't talked about oil and Israel and whether or not "protecting one's interests" is just a euphemism for taking stuff that belongs to somebody else.